1. Field of the invention
This invention relates to a method of and an apparatus for high-frequency heating of a rocker arm to braze a chip thereto.
2. Description of the Related Art
It is a normal practice to use a heating furnace to braze a chip to a rocker arm which is one of the parts constituting an internal combustion engine. In the heating furnace using electric heat, gas, or heavy oil as energy source, a heavily excess heat is consumed as compared to the heat required to heat a part of the rocker arm. As a result, entire manufacturing equipment becomes large in size, expensive in cost and complex in structure associated with awkward maintenance requirements.
As disclosed in Japanese Patent Publication No. 3-40084, there is known a method wherein a designated part of the rocker arm to which a chip is attached is high-frequency heated and then air-cooled to thereby braze the chip to the rocker arm with a reduced energy consumption.
In the above conventional method, however, the high-frequency heating is carried out in the normal atmosphere of a workshop, resulting in an oxide film developed in particular on the surface of the ferrous chip. A problem has been therefore pointed out that the above conventional method requires an additional process of removing the oxide film from the chip after the high-frequency heating, making the entire process of chip brazing inefficient.